Hybrid particle mix for seal and plug quality enhancement

ABSTRACT

A hybrid particle mix lost circulation material (LCM) is provided. The hybrid particle mix LCM includes date palm seed particles produced from date palm seeds and scrap tire particles produced from scrap tires. The LCM may include date palm seed particles in the range of about 50 wt % to about 80% and scrap tire particles in the range of about 50 wt % to about 20 wt %. Methods of lost circulation control and manufacture of a hybrid particle mix LCM are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority from U.S.Non-provisional application Ser. No. 15/889,668 filed Feb. 6, 2018, andtitled “ARC HYBRID PARTICLE MIX FOR SEAL AND PLUG QUALITY ENHANCEMENT,”a copy of which is incorporated by reference in its entirety forpurposes of United States patent practice.

BACKGROUND Field of the Disclosure

The present disclosure generally relates to controlling lost circulationin a wellbore during drilling with a drilling fluid. More specifically,embodiments of the disclosure relate to a lost circulation material(LCM).

Description of the Related Art

Lost circulation is one of the frequent challenges encountered duringdrilling operations. Lost circulation can be encountered during anystage of operations and occurs when drilling fluid (such as drillingmud) pumped into a well returns partially or does not return to thesurface. While some fluid loss is expected, excessive fluid loss is notdesirable from a safety, an economical, or an environmental point ofview. Lost circulation is associated with problems with well control,borehole instability, pipe sticking, unsuccessful production tests, poorhydrocarbon production after well completion, and formation damage dueto plugging of pores and pore throats by mud particles. In extremecases, lost circulation problems may force abandonment of a well.

Lost circulation can occur in various formations, such as naturallyfractured formations, cavernous formations, and high permeableformations. Lost circulation can be categorized by the amount of fluidor mud lost as seepage type, moderate type, severe type, and total loss.The extent of the fluid loss and the ability to control the lostcirculation with an LCM depends on the type of formation in which thelost circulation occurs. Formations with low permeability zones, thatis, those with microscopic cracks and fissures, usually have seepagetype lost circulation. Other formations may experience lost circulationif an improper mud weight is used while drilling.

SUMMARY

Lost circulation materials (LCMs) are used to mitigate the lostcirculation by blocking the path of the drilling fluid (such as drillingmud) into the formation. The type of LCM used in a lost circulationsituation depends on the extent of lost circulation and the type offormation. Different types of LCMs such as granular, fibrous and flakymaterials are frequently used, either alone or in combination, tocontrol loss of circulation. For example, different types of sizedparticulate lost circulation materials are used to combat loss ofcirculation either as a background material in the mud system or as acomponent of an LCM pill or a loss control slurry. The purpose of theparticulate material is to assist in creation of an effective and stableseal or plug in the loss zone to maintain the integrity of the seal orplug in changing borehole conditions.

Existing particle-based LCMs may create seals or plugs with zero ornegligible ductility, malleability, and resiliency. Consequently, theplugs or seals created by such LCMS often fail under changing boreholeconditions, such as high surge and swabbing pressures, tectonicactivities, and effective stress changes. Some existing LCMs usegraphite-based resilient materials are used in LCM pills to improve theductile, malleable and resilience behavior of set seals or plugs.However, these graphite-based materials may be expensive, may not beavailable locally, and may have limited ductile, malleable and resilientcharacteristics.

In one embodiments, a method to control lost circulation in a lostcirculation zone in a wellbore is provided. The method includesintroducing an altered drilling fluid into the wellbore such that thealtered drilling fluid contacts the lost circulation zone and reduces arate of lost circulation into the lost circulation zone, where thealtered drilling fluid includes a drilling fluid and a lost circulationmaterial (LCM). The LCM includes a first plurality of particles producedfrom date tree seeds and a second plurality of particles produced fromscrap tires. In some embodiments, the altered drilling fluid consists ofthe drilling fluid and the LCM. In some embodiments, the LCM consists ofthe first plurality of particles produced from date tree seeds and thesecond plurality of particles produced from scrap tires. In someembodiments, the first plurality of particles present in an amount inthe range of 50% by weight to 80 by weight and the second plurality ofparticles present in an amount in the range of 50% by weight to 20% byweight. In some embodiments, the LCM has a concentration of at least 20pounds-per-barrel (ppb) in the altered drilling fluid. In someembodiments, each of the first plurality of particles produced from datetree seeds has a diameter in the range of 500 microns to 4000 microns.In some embodiments, each of the second plurality of particles producedfrom scrap tires has a diameter in the range of 2000 microns to 8000microns. In some embodiments, the first plurality of particles include afirst plurality of untreated particles produced from untreated date treeseeds.

In another embodiments, an altered drilling fluid is provided thatincludes a drilling fluid and a lost circulation material (LCM). The LCMincludes a first plurality of particles produced from date tree seedsand a second plurality of particles produced from scrap tires. In someembodiments, the LCM consists of the first plurality of particlesproduced from date tree seeds and the second plurality of particlesproduced from scrap tires. In some embodiments, the first plurality ofparticles present in an amount in the range of 50% by weight to 80% byweight and the second plurality of particles present in an amount in therange of 50% by weight to 20% by weight. In some embodiments, the LCMhaving a concentration of at least 20 pounds-per-barrel (ppb) in thealtered drilling fluid. In some embodiments, each of the first pluralityof particles produced from date tree seeds has a diameter in the rangeof 500 microns to 4000 microns. In some embodiments, each of the secondplurality of particles produced from scrap tires has a diameter in therange of 2000 microns to 8000 microns.

In another embodiment, a lost circulation material (LCM) composition isprovided. The LCM composition includes a first plurality of particlesproduced from date tree seeds and a second plurality of particlesproduced from scrap tires. In some embodiments, the LCM consists of thefirst plurality of particles from date tree seeds and the secondplurality of particles produced from scrap tires. In some embodiments,the first plurality of particles present in an amount in the range of50% by weight to 80% by weight and the second plurality of particlespresent in an amount in the range of 50% by weight to 20% by weight. Insome embodiments, each of the first plurality of particles produced fromdate tree seeds has a diameter in the range of 500 microns to 4000microns. In some embodiments, each of the second plurality of particlesproduced from scrap tires has a diameter in the range of 2000 microns to8000 microns. In some embodiments, the first plurality of particlesincluding a first plurality of untreated particles produced fromuntreated date tree seeds.

In another embodiment, a method of forming a lost circulation material(LCM) is provided. The method includes processing date tree seeds toproduce a first plurality of particles, processing scrap tires toproduce a second plurality of particles, and mixing a first amount ofthe first plurality of particles and a second amount of the secondplurality of particles to form the LCM. In some embodiments, processingthe date tree seeds to produce the first plurality of particles includesgrinding the date tree seeds. In some embodiments, each of the firstplurality of particles has a diameter in the range of 500 microns to4000 microns. In some embodiments, processing the scrap tires to producethe second plurality of particles includes shredding the scrap tires andgrinding the shredded scrap tires to produce the second plurality ofparticles. In some embodiments, the first plurality of particles presentin an amount in the range of 50% by weight to 80% by weight and thesecond plurality of particles present in an amount in the range of 50%by weight to 20% by weight. In some embodiments, each of the secondplurality of particles produced from scrap tires has a diameter in therange of 2000 microns to 8000 microns.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process for the production and use of a hybrid particle mixLCM formed from date palm seed particles and scrap tire particles inaccordance with an embodiment of the disclosure;

FIG. 2 is a bar graph of the particle size distribution of an examplehybrid particle mix in accordance with an embodiment of the disclosure;

FIG. 3 is a graph of the load-displacement behavior of an example hybridparticle mix, a 100% date palm seed particle formulation, and a 100%scrap tire particle formulation resulting from a compression test inaccordance with an embodiment of the disclosure;

FIG. 4 is a graph of the load-displacement behavior of a 100% date palmseed particle formulation resulting from a resiliency test in accordancewith an embodiment of the disclosure;

FIG. 5 is a graph of the load-displacement behavior of a 100% scrap tireparticle formulation resulting from a resiliency test in accordance withan embodiment of the disclosure; and

FIG. 6 is a graph of the load-displacement behavior of a hybrid particlemix resulting from a resiliency test in accordance with an embodiment ofthe disclosure.

DETAILED DESCRIPTION

The present disclosure will be described more fully with reference tothe accompanying drawings, which illustrate embodiments of thedisclosure. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the illustratedembodiments. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art.

As a wellbore is drilled, a drilling fluid is continuously pumped intothe wellbore to clear and clean the wellbore and the filings. Thedrilling fluid is pumped from a mud pit into the wellbore and returnsagain to the surface. A lost circulation zone is encountered when theflow rate of the drilling fluid that returns to the surface is less thanthe flow rate of the drilling fluid pumped into the wellbore. It is thisreduction or absence of returning drilling fluid that is referred to aslost circulation.

Embodiments of the disclosure include a particle mix LCM (referred to asa “hybrid particle mix” LCM) that includes a mix of date palm seedparticles obtained from date palm seeds and scrap tire particlesobtained from scrap tires. The hybrid particle mix LCM may mitigate orprevent lost circulation in a well, as well as provide seepage controland minimize or prevent fluid loss. As used in the disclosure, the termdate palm seeds refers to the seeds produced from date trees (alsoreferred to as “date palms”), such as used in the production of datefruits (also referred to as “dates”).

With the foregoing in mind, a hybrid particle mix LCM may includeparticles formed from ground date tree seeds and particles formed fromground scrap tires. In some embodiments, the particles formed fromground scrap tires may include crumb rubber. In some embodiments, thehybrid particle mix LCM may include date palm seed particles in therange of about 50% by weight (wt %) to about 80% and scrap tireparticles in the range of about 50 wt % to about 20 wt %. In someembodiments, the hybrid particle mix LCM includes 64 wt % date palm seedparticles and 36 wt % scrap tire particles. In some embodiments, theresulting hybrid particle mix may have a bimodal particle sizedistribution.

The presence of two types of particles with different properties mayenable the hybrid particle mix LCM to form a structure (for example, aseal or plug) in subsurface conditions that can adsorb strain energywhen deformed elastically under the in-situ conditions and desorb strainenergy when the subsurface in-situ conditions change with changingwellbore conditions. For example, the date palm seed particles by morerigid as compared to the scrap tire particles, while the scrap tireparticles may be more ductile, malleable, and resilient as compared tothe date palm seed particles. The combination of both particles in thehybrid particle mix may enable the in-situ formation of a seal or plugthat has improved malleability, ductility, and resiliency as compared toexisting LCMs. The combination of both particles in the hybrid particlemix may further enable the formation of a seal or plug having improvedseal hardening characteristics as compared to existing LCMs, such as byimproving the plastic deformation characteristics that enables particledislocation, readjustment, realignment, resetting, and the like withoutmacroscale failure of the set plug or seal. Finally, the combination ofboth particles in the hybrid particle mix may further enable theformation of a seal or plug having improved stability as compared toexisting LCMs, such as by decreasing the radial stress effect due to theimproved resilient, ductile and malleable characteristics of the setseal and plug and improved resistance to internal cracking andfracturing.

Hybrid Particle Mix LCM Manufacture and Use

In some embodiments, a hybrid particle mix LCM includes date palm seedparticles and scrap tire particles. The date palm seed particles includeparticles manufactured from date palm seeds. The date palm seeds may beobtained from pruning waste and date processing plants to provide asustainable source of material for the hybrid particle mix LCM.Moreover, local sources of date tree waste may reduce the cost ofimported LCM products, components, or both. The date palm seeds may beobtained from the species phoenix dactylifera. It should be appreciatedthat, in some embodiments, the date palm seeds may be obtained fromgenetically modified date trees (that is, genetically modified organisms(GMOs)). In some embodiments, the date palm seeds may be prepared bycleaning the date palm seeds before use or processing, such as bywashing the date palm seeds.

The scrap tire particles may be obtained from scrap tires (also referredto as “waste tires”). The scrap tires may be obtained from tirerecycling facilities, tire disposal locations, and the like. The scraptires may be shredded and ground to produce the scrap tire particles. Insome embodiments, unwanted components (for example, metallic components)may be separated from the scrap tires during processing (for example,via a magnetic separator).

In some embodiments, the date palm seed particles may include particleshaving the following particle size distribution, as determined by thediameters of the particles passed or retained in mesh openings: about4000 microns (μm) to about 2000 microns (that is, particles passingthrough sieve mesh size no. 5 and retained in sieve mesh size no. 10),about 2000 microns to about 1000 microns (that is, particles passingthrough sieve mesh size no. 10 and retained in sieve mesh size no. 18),and about 1000 microns to about 500 microns (that is, particles passingthrough sieve mesh size no. 18 and retained in sieve mesh size no. 35).

In some embodiments, the scrap tire particles may include particleshaving the following particle size distribution, as determined by thediameters of the particles passed or retained in mesh openings: about8000 microns to about 4000 microns (that is, particles passing throughsieve mesh size no. 5/16 and retained in sieve mesh size no. 5) andabout 4000 microns to about 2000 microns (that is, particles passingthrough sieve mesh size no. 5 and retained in sieve mesh size no. 10).

In some embodiments, the hybrid particle mix LCM may include date palmseed particles in the range of about 50% by weight (wt %) to about 80%and scrap tire particles in the range of about 50 wt % to about 20 wt %.In some embodiments, the hybrid particle mix LCM includes 64 wt % datepalm seed particles and 36 wt % scrap tire particles.

In some embodiments, the date palm seeds may include untreated date palmseeds to preserve the environmentally-friendly and biodegradableproperties of the manufacturing process, the date palm seeds, and theresulting LCM composition. As used in the disclosure, the term“untreated” or “without treating” refers to not treated with alkali oracid, not bleached, not chemically altered, not oxidized, and withoutany extraction or reaction process other than possibly drying of water.The term “untreated” or “without treatments” does not encompass grindingor heating to remove moisture but does encompass chemical or otherprocesses that may change the characteristics or properties of theparticles. In such embodiments, the date palm seed particles may bemanufactured without treating before, during, or after crushing,grinding, drying, or any other processing.

In some embodiments, the hybrid particle mix LCM may be added directlyto a drilling fluid, such as a drilling mud, to create an altereddrilling fluid having the hybrid particle mix LCM. For example, in someembodiments, the hybrid particle mix LCM may be added to (for example,blended with) an oil-based drilling mud or a water-based drilling mud.In some embodiments, the hybrid particle mix LCM may be added at the mudpit of a mud system. In some embodiments, the hybrid particle mix LCMmay be added to a drilling fluid in an amount in the range of about 20parts-per-billion mass (ppb) to about 50 ppb. After addition of thehybrid particle mix LCM to a drilling fluid, the altered drilling fluidmay be circulated at a pump rate effective to position the altereddrilling fluid into contact with a lost circulation zone in a wellbore,such that the hybrid particle mix LCM alters the lost circulation zone(for example, by entering and blocking porous and permeable paths,cracks, and fractures in a formation in the lost circulation zone, suchas forming a structure (for example, a plug or seal) in a mouth orwithin a fracture).

As noted in the disclosure, the properties of the hybrid particle LCMmay prevent damage or degradation of the structures (for example, plugsand seals) formed from the hybrid particle mix LCM under changingsubsurface conditions after placement downhole in a lost circulationzone. Additionally, in contrast to fluid loss additives used to preventfluid loss in drilling fluids, the hybrid particle LCM may prevent theloss of whole mud in lost circulation zones.

FIG. 1 depicts a process 100 for the production and use of a hybridparticle mix LCM in accordance with an example embodiment of thedisclosure. As shown in FIG. 1, date tree seeds may be collected (block102), such as from date tree waste produced by date tree farming anddate processing industries. In some embodiments the date palm seeds maybe cleaned, such as by a high pressure water or air jet, to remove dirt,dust, and other foreign substances. The collected date palm seeds may beground to produce particles from the date palm seeds (block 104). Insome embodiments, the collected date palm seeds may be ground using asuitable commercial grinder that produces a specific range of particlesizes (for example, particles having a specific range of particlediameters).

As also shown in FIG. 1, scrap tires may be collected, such as from tirerecycling facilities or tire disposal locations (block 106). In someembodiments, tires may be collected and transported to another facilityfor processing as described in the disclosure. In some embodiments thetires may be cleaned, such as by a high pressure water or air jet, toremove dirt, dust, and other foreign substances. The collected tires maybe shredded and ground to produce particles from the scrap tires (block108). In some embodiments, the collected scrap tires may be ground usinga suitable commercial grinder that produces a specific range of particlesizes (for example, particles having a specific range of particlediameters). In some embodiments, unwanted components (for example,metallic components) may be separated from the scrap tires duringprocessing (for example, via a magnetic separator).

The date palm seed particles and the scrap tire particles may then bemixed to form a hybrid particle mix having both particles (block 110).In some embodiments, the mix of date palm seed particles and the scraptire particles may be packed for transportation and use. In someembodiments, a suitable amount of packed mixed particles may then betransported to an oil and gas operations site for use as an LCM.

The hybrid particle mix LCM may be added directly to a drilling fluid(block 112), such as a drilling mud, to create an altered drilling fluidhaving the hybrid particle mix LCM. For example, in some embodiments,the hybrid particle mix LCM may be added to (for example, blended with)an oil-based drilling mud or a water-based drilling mud. In someembodiments, the hybrid particle mix LCM may be added at the mud pit ofa mud system. After addition of the hybrid particle mix LCM to adrilling fluid, the altered drilling fluid may be circulated at a pumprate effective to position the drilling fluid into contact with a lostcirculation zone in a wellbore, such that the hybrid particle mix LCMalters the lost circulation zone (for example, by entering and blockingporous and permeable paths, cracks, and fractures in a formation in thelost circulation zone). As previously stated, the hybrid particle mixLCM may form resilient structures (for example, plugs or seals) atopenings of paths, cracks, and fractures in a loss zone. In someembodiments, the reduced rate of lost circulation may be negligible. Insome embodiments, the hybrid particle mix LCM may be introduced via anopen ended drill pipe to place the LCM in the lost circulation zone.

In other embodiments, the hybrid particle mix LCM and one or moreadditional LCMs may be added to a drilling fluid, such as a drillingmud, to create an altered drilling fluid having the LCMs. For example,in some embodiments, the hybrid particle mix LCM and one or moreadditional LCMs may be added to an oil-based drilling mud or awater-based drilling mud. In other embodiments, the hybrid particle mixLCM may be added to a cement slurry for use in a cementing operation.

In some embodiments, the hybrid particle mix LCM may be mixed with acarrier fluid, a viscosifier, or both. In some embodiments, a hybridparticle mix LCM homogenous suspension, slurry, or pill may be formed.For example, a specific carrier fluid, viscosifier, or combinationthereof may be selected to form a homogenous suspension, slurry, or pillhaving the hybrid particle mix LCM. The homogenous suspension or pillmay be added to a drilling fluid and used in the manner similar to thehybrid particle mix LCM described in the disclosure.

Examples

The following examples are included to demonstrate embodiments of thedisclosure. It should be appreciated by those of skill in the art thatthe techniques and compositions disclosed in the example which followsrepresents techniques and compositions discovered to function well inthe practice of the disclosure, and thus can be considered to constitutemodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or a similar result without departing from the spirit and scope ofthe disclosure.

The following non-limiting examples of a hybrid particle mix LCM wereprepared and evaluated against a 100% date palm seed formulation and a100% scrap tire particle formulation. The hybrid particle mix LCM wasprepared by combining 64% by weight date palm seed particles and 35% byweight scrap tire particles with different particle size distribution(PSD) to provide a bimodal particle size distribution in the resultanthybrid particle mix LCM. The date palm seed particles and scrap tireparticles were mixed together using a low shear mixing apparatus to forma homogenous mix of particles while maintaining the particle sizedistribution without damaging or degrading the particles.

The date palm seed particles had the following particle sizedistribution (PSD), as determined by the diameters of the particlespassed or retained in mesh openings: about 4000 microns (μm) to about2000 microns (that is, particles passing through sieve mesh size no. 5and retained in sieve mesh size no. 10), about 2000 microns to about1000 microns (that is, particles passing through sieve mesh size no. 10and retained in sieve mesh size no. 18), and about 1000 microns to about500 microns (that is, particles passing through sieve mesh size no. 18and retained in sieve mesh size no. 35).

The scrap tire particles had the following particle size distribution(PSD), as determined by the diameters of the particles passed orretained in mesh openings: about 8000 microns to 4000 microns (that is,particles passing through sieve mesh size no. 5/16 and retained in sievemesh size no. 5) and about 4000 microns to about 2000 microns (that is,particles passing through sieve mesh size no. 5 and retained in sievemesh size no. 10).

As shown by the particle size distributions, at surface conditions thescrap tire particles had an overlapping particle size that was equal toone size range of the date palm seed particles. However, the scrap tireparticle size may be significantly reduced at subsurface conditions dueto pressure. This allows easy infiltration of the scrap tire particlesinto the date palm seed particle matrix under the pressure downhole,enabling the scrap tire particles to act as a filler material. Due tothe relatively greater resiliency of the scrap tire particles ascompared to the date palm seed particles, the seal or plug formed by thehybrid particle mix LCM may maintain integrity and fit when the pressureis reduced or removed.

As mentioned supra, the example hybrid particle mix LCM prepared fromthe date palm seed particles and scrap tire particles with the describedparticle size distributions had a bimodal particle size distribution.FIG. 2 is a bar graph 200 of the particle size distribution of theexample hybrid particle mix in accordance with an embodiment of thedisclosure. As shown in FIG. 2, the y-axis 204 depicts the differential% of particles retained and the x-axis 206 depicts the particle size (inmicrons). The particle size distribution illustrates a bimodal particlesize distribution a first mode (illustrated by bar 206) at about 1000microns and a second mode (illustrated by bar 208) at about 2000microns.

The example hybrid particle mix LCM was evaluated to determine theimprovement to the ductility, malleability, and resiliency provided bythe example hybrid particle mix. The example hybrid particle mix LCM, adate palm seed particle formulation having 100% date palm seedparticles, and a scrap tire particle formulation having 100% scrap tireparticles were tested using a resilience testing apparatus, such as isdescribed in U.S. application Ser. No. 15/802,870, now U.S. PublicationNo. 2019/0137371. For example, a suitable resilience testing apparatusmay include a cylindrical test cell with an open end and a closed endand a probe with a disc piston that applies a load on a sample placed inthe test cell. A movement mechanism may be attached to a carrier armthat applies a load to the sample in the test cell by moving the probeand compressing the sample. The resilience testing apparatus may becoupled to a computer to monitor and control the test parameters (suchas strain percentage applied to the sample) and determine various testresults.

The load-displacement behavior of the hybrid particle mix LCM and theother formulations was determined at a displacement rate of 1 millimeter(mm) per second (sec). FIG. 3 depicts a graph 300 of theload-displacement behavior of the hybrid particle mix LCM, the date palmseed particle formulation, and the scrap tire particle formulation. Asshown in FIG. 3, the y-axis 302 depicts force (in kilograms (kg)) andthe x-axis 304 depicts distance (mm). As shown in the graph 300, theline 306 corresponds to the date palm seed particle formulation, line308 corresponds to the example hybrid particle mix formulation, and line310 corresponds to the scrap tire particle formulation. As shown in FIG.3, the steep slope of the line 306 corresponding to the date palm seedparticle formulation indicates the lack of or negligible malleability ofthe 100% date palm seed particle formulation. In contrast, theprogressive rise of the line 310 corresponding to the scrap tireparticle formulation with the large displacement at the top of the line310 to register the same force (load) as the other tested compositionsindicate large malleability of the scrap tire particles. Accordingly,mixing proportions of the date palm seed particles and scrap tireparticles may produce a hybrid particle mix with intermediatemalleability as compared to either of the particles alone. Thus, asshown in FIG. 3, the line 308 corresponding to the hybrid particle mixLCM shows a load-displacement behavior in-between the date palm seedparticle formulation and scrap tire particle formulation. The line 308thus illustrates the malleability of the hybrid particle mix LCM due tothe mix of particles and may be expected to improve the stability ofseals and plugs formed from the LCM under changing subsurfaceconditions.

The material stiffness (also referred to as “compression”) for thehybrid particle mix LCM, the 100% date palm seed particle formulation,and the 100% scrap tire formulation was determined from a linear fit tothe most linear portion of the curves 308, 306, and 310 respectively ofFIG. 3. Table 1 shows the determined material stiffness for eachformulation:

TABLE 1 MATERIAL STIFFNESS DETERMINED FROM LOAD-DISPLACEMENT CURVES Cutoff Load Stiffness Correlation Samples (grams-force ((gf) (kg/mm)Coefficient 100% Date palm 67250.551 31.463 0.999 seed particle HybridParticle mix 5.293 0.993 100% Scrap tire 2.156 0.997 particles

In a second experiment, the load-displacement behaviors of the hybridparticle mix LCM, the 100% date palm seed particle formulation, and the100% scrap tire formulation were evaluated using the resilience testingapparatus and a compression cycle and a decompression cycle. The testwas conducted at a 10% strain using the following test procedure:

1. Place a sufficient amount of the test sample into the test cell sothat the sample top is 2 centimeters (cm) below the open end of the testcell and level;

2. Set the circular foot of the probe above the top of the test sampleand set a trigger force of 3 gf that initiates data recording;

3. Compress the test sample until the specified strain percentage isreached at a displacement rate of 1 mm/sec (referred to as a“compression cycle”);

4. Record the total energy stored at the end of the compression cycle;

5. Hold the probe in pace for 1 minute;

6. Withdraw the probe at a rate of 1 mm/sec until the probe iscompletely withdrawn from the test sample (referred to a “decompressioncycle”);

7. Record the total energy released at the end of the decompressioncycle; and

8. Determine the coefficient of resilience by dividing the desorbedstrain energy released during the decompression cycle by the absorbedstrain energy stored during the compression cycle of the test.

FIG. 4 depicts graph 400 of the results of the resilience test of the100% the date palm seed particle formulation. As shown in FIG. 4, they-axis 402 depicts force (in kilograms (kg)) and the x-axis 404 depictsdistance (mm). The graph 400 illustrates a compression curve 406generating during a compression cycle of the resilience test. Thecompression cycle of the resilience test of the 100% date palm seedparticle formulation was automatically terminated for exceeding thecapacity of the resilience test equipment. The graph 400 does notinclude a decompression curve as the 100% date palm seed particleformulation did not exhibit any springing or bouncing back during thedecompression cycle of the resilience test.

FIG. 5 depicts graph 500 of the results of a resilience test of the 100%scrap tire particle formulation. As shown in FIG. 5, the y-axis 502depicts force (in kg) and the x-axis 504 depicts distance (in mm). Thegraph 500 illustrates a compression curve 506 generating during acompression cycle of the resilience test and a decompression curve 508generating during a decompression cycle of the test. As will beappreciated, the areas below the compression curve 506 and thedecompression curve 508 may be used to determine a coefficient ofresilience according to the following Equation 1:

$\begin{matrix}{{COR} = \frac{Ad}{Ac}} & (1)\end{matrix}$

Where COR is the coefficient of resilience, Ad is the area under thedecompression curve, and Ac is the area under the compression curve.

FIG. 6 depicts graph 600 of the results of a resilience test of thehybrid particle mix formulation. As shown in FIG. 6, the y-axis 602depicts force (in kg) and the x-axis 604 depicts distance (in mm). Thegraph 600 illustrates a compression curve 606 generating during acompression cycle of the resilience test of the hybrid particle mixformulation and a decompression curve 608 generating during adecompression cycle of the test. As discussed supra, Equation 1 may beused to determine a coefficient of resilience based on the areas underthe compression curve 606 and the decompression curve 608.

Table 2 shows the results of the resiliency test for the hybrid particlemix LCM, the 100% date palm seed particle formulation, and the 100%scrap tire formulation, and the coefficient of resiliency determined forthe 100% scrap tire formulation and the hybrid particle mix formulation:

TABLE 2 RESULTS OF RESILIENCY TEST AND DETERMINED COEFFICIENT OFRESILIENCE Area A Area B (Area (Area below below Coeff- compres-decompres- icient Peak Distance sion sion of Test load traveled atcurve, curve, Resil- Sample (kgf) 10% strain kgf-mm) kgf-mm) iency 100%Date 67.67 2.5 (test 51.801 N/A N/A palm seed automatically particleterminated for exceeding equipment capacity) 100% 1.77 6.26 3.994 3.6900.924 Scrap tire particles Hybrid 8.42 6.29 19.192 14.832 0.773 particlemix

As shown in Table 2, the hybrid particle mix has a coefficient ofresilience greater than 0.5, indicating a significant amount ofresiliency. The resiliency characteristics of the hybrid particle mixshow the capability of the formulation as an LCM having improved sealand plug stability under changing subsurface conditions. The test resultdata in Table 2 also demonstrates that the resiliency of a hybridparticle mix may be increased by increasing the percentage of scrap tireparticles in the formulation.

In a third experiment, the sealing and plugging capability of the hybridparticle mix was evaluated using a 2 millimeter (mm) slotted disc and aPermeability Plugging Tester (also referred to as “PPT” or “PorePlugging Test” apparatus) manufactured by OFI Testing Equipment, Inc.,of Houston, Tex., USA. The tests were conducted at conditions of about212° F. and about 500 psi differential pressure. For the pluggingefficiency tests, the hybrid particle mix formulation was incorporatedinto a 65 pounds per cubic foot (pcf) bentonite mud. The composition ofthe 65 pcf bentonite mud with mud components expressed inpounds-per-barrels (lb/bbl) is shown in Table 3:

TABLE 3 COMPOSITION OF 65 PCF BENTONITE MUD Mud Component lb/bbl Water340.67 Bentonite 25.00 Caustic Soda 0.25 Soda Ash 0.25

The test was conducted using the Permeability Plugging Tester apparatusand the following plugging efficiency test procedure:

1. Set the temperature controller/thermostat to the testing temperature;

2. Check the condition of the O-rings in the groove at the top of thetest cell of the Permeability Plugging Tester apparatus and in the cellend cap and replace the O-rings if needed;

3. Apply a thin coating of high temperature grease to all the O-rings,including the two O-rings on the piston of the Permeability PluggingTester apparatus;

4. Screw the T-bar of the Permeability Plugging Tester apparatus intothe piston, install into the bottom end of the test cell, position thepiston about 1 inch into the cell bore, and remove the T-bar;

5. Add a volume of hydraulic oil to the test cell using the hydraulichand pump of the Permeability Plugging Tester apparatus;

6. Install all the O-rings and secure the end cap of the cell inposition such that oil flows from the hole in the end cap to ensure noair is trapped;

7. Install the valve stem into the bottom end cap of the cell, tightenthe valve stem, and disconnect from the hydraulic hand pump of thePermeability Plugging Tester apparatus;

8. Place the cell upright on a suitable stand;

9. Pour a test sample of a homogenous mixture of 275 milliliters (ml) ofthe 65 pcf bentonite mud and 30 grams of an LCM into the test cell;

10. Install an O-ring into the top of the cell below the 2 mm slotteddisc;

11. Place the 2 mm slotted disc on top of the O-ring;

12. Insert the end cap on the top of the disc, screw down the threadedretaining ring, and fully tighten;

13. Tighten the top stem of the test cell;

14. Place the cell into the heating jacket of the Permeability PluggingTester apparatus;

15. Connect a pressure hose from the hydraulic hand pump to the bottomof the test cell via a quick connector and ensure the bottom stem isclosed;

16. Connect the back pressure hose/sample collector to the top stem ofthe test cell, ensuring that the locking pin is in place, close thepressure relief valve on the side of the hydraulic hand pump, apply thetesting pressure via the back pressure regulator to the top of the testcell, and close the top valve.

17. Place a thermometer into the hole at the top of the test cell, waituntil the testing temperature is reached, and monitor the cell pressurewhile heating and bleed off pressure if necessary by opening thepressure relived valve on the side of the hydraulic hand pump;

18. Once the test sample has reached the testing temperature, pump thehydraulic hand pump until the pump gauge shows the testing pressure plusthe required back pressure;

19. Apply the required back pressure to the top of the cell, open thetop valve, and pump the hydraulic hand pump to reestablish the testingpressure;

20. To determine the spurt volume, collect the fluid from the backpressure collector in a measuring cylinder and record the amount,ensuring that all the fluid has been expelled;

21. Collect the fluid periodically over a 30 minute time period andcheck the back pressure gauge to ensure that the pressure remains lessthan the pressure threshold (about 3000 psi) of the built-in safety discof the Permeability Plugging Tester apparatus and avoid expulsion of hothydraulic oil;

22. Record the spurt loss, total leak off, and PPT values over the 30minute time period and record the cake thickness after dismantling thetest cell.

Table 4 shows the results of plugging efficiency tests for the hybridparticle mix formulation at 20 pounds-per-barrel (ppb) concentrations inthe 65 pcf bentonite mud, with the spurt loss, fluid loss, total leakoff, and PPT value measured in cubic centimeters (cc) and the cakethickness measured in mm:

TABLE 4 PLUGGING EFFICIENCY TEST RESULTS FOR HYBRID PARTICLE MIX LCM MudSpurt Fluid Total PPT System LCM Concentration Loss Loss Leak-off Value65 pcf Hybrid 20 ppb 9 ml 0 9 ml 18 ml Bentonite Particle Mud Mix

As shown in Table 4, the plugging efficiency tests show that after aninitial sport loss of 9 ml of mud through the slots of the PPT disc, thehybrid particle mix formulation was able to completely stop the loss ofwhole mud and exhibited zero fluid loss at 20 ppb. The test demonstratesthat the hybrid particle mix is capable of effectively reducing oreliminating loss circulation due to the combined characteristics of thedate palm seed particles and the scrap tire particles. Moreover, astructure (for example, a plug or seal) formed by the hybrid particlemix will have resilient characteristics that enable the plug or seal toreform from or avoid permanent damage or degradation to the plug or sealunder changing subsurface conditions.

Ranges may be expressed in the disclosure as from about one particularvalue, to about another particular value, or both. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value, to the other particular value, or both, along withall combinations within said range.

Further modifications and alternative embodiments of various aspects ofthe disclosure will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the embodiments described inthe disclosure. It is to be understood that the forms shown anddescribed in the disclosure are to be taken as examples of embodiments.Elements and materials may be substituted for those illustrated anddescribed in the disclosure, parts and processes may be reversed oromitted, and certain features may be utilized independently, all aswould be apparent to one skilled in the art after having the benefit ofthis description. Changes may be made in the elements described in thedisclosure without departing from the spirit and scope of the disclosureas described in the following claims. Headings used described in thedisclosure are for organizational purposes only and are not meant to beused to limit the scope of the description.

What is claimed is:
 1. A method to control lost circulation in a lostcirculation zone in a wellbore, comprising: introducing an altereddrilling fluid into the wellbore such that the altered drilling fluidcontacts the lost circulation zone and reduces a rate of lostcirculation into the lost circulation zone, where the altered drillingfluid comprises a drilling fluid and a lost circulation material (LCM),wherein the LCM has a concentration of at least 20 parts-per-billion inthe altered drilling fluid, wherein the LCM comprises: a first pluralityof particles produced from date tree seeds, wherein each of the firstplurality of particles produced from date tree seeds has a diameter inthe range of 500 microns to 4000 microns; and a second plurality ofparticles produced from scrap tires; wherein the LCM has a coefficientof resiliency of at least 0.5 and prevents the loss of whole mud in thelost circulation zone.
 2. The method of claim 1, wherein the altereddrilling fluid consists of the drilling fluid and the LCM.
 3. The methodof claim 1, wherein the LCM consists of the first plurality of particlesproduced from date tree seeds and the second plurality of particlesproduced from scrap tires.
 4. The method of claim 1, wherein the firstplurality of particles comprise an amount in the range of 50% by weightto 80 by weight and the second plurality of particles comprise an amountin the range of 50% by weight to 20% by weight.
 5. The method of claim1, wherein the LCM comprises a concentration of at least 20pounds-per-barrel (ppb) in the altered drilling fluid.
 6. The method ofclaim 1, wherein each of the second plurality of particles produced fromscrap tires has a diameter in the range of 2000 microns to 8000 microns.7. The method of claim 1, wherein the first plurality of particlescomprise a first plurality of untreated particles produced fromuntreated date tree seeds.
 8. A method to control lost circulation in alost circulation zone in a wellbore, comprising: introducing an altereddrilling fluid into the wellbore such that the altered drilling fluidcontacts the lost circulation zone and reduces a rate of lostcirculation into the lost circulation zone, where the altered drillingfluid comprises a drilling fluid and a lost circulation material (LCM),wherein the LCM has a concentration of at least 20 parts-per-billion inthe altered drilling fluid, wherein the LCM comprises: a first pluralityof particles produced from date tree seeds; and a second plurality ofparticles produced from scrap tires, wherein each of the secondplurality of particles produced from scrap tires has a diameter in therange of 2000 microns to 8000 microns; wherein the LCM has a coefficientof resiliency of at least 0.5 and prevents the loss of whole mud in thelost circulation zone.
 9. The method of claim 8, wherein the altereddrilling fluid consists of the drilling fluid and the LCM.
 10. Themethod of claim 8, wherein the LCM consists of the first plurality ofparticles produced from date tree seeds and the second plurality ofparticles produced from scrap tires.
 11. The method of claim 8, whereinthe first plurality of particles comprise an amount in the range of 50%by weight to 80 by weight and the second plurality of particles comprisean amount in the range of 50% by weight to 20% by weight.
 12. The methodof claim 8, wherein the LCM comprises a concentration of at least 20pounds-per-barrel (ppb) in the altered drilling fluid.
 13. The method ofclaim 8, wherein each of the first plurality of particles produced fromdate tree seeds has a diameter in the range of 500 microns to 4000microns.
 14. The method of claim 8, wherein the first plurality ofparticles comprise a first plurality of untreated particles producedfrom untreated date tree seeds.